BR34L02-W Ver la hoja de datos (PDF) - ROHM Semiconductor
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BR34L02-W Datasheet PDF : 17 Pages
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●WP EFFECTIVE TIMING
WP is fixed to "H" or "L" usually . But in case of controlling WP to cancel the write command, please pay attention to “WP
effective timing” as follows.
During write command input , write command is canceled by controlling WP "H" within the WP cancellation effective
period.
The period from the start condition to the rising edge of the clock which take in DO of the data (the first byte of the data for
Page Write) is the cancellation invalid period. WP input is don't care during the period. Setup time for rising edge of the
SCL which takes in DO must be more than 100ns.
The period from the rising edge of SCL which takes in DO to the end of internal write cycle (tWR) is the cancellation
effective period. In case of setting WP to "H" during tWR, WRITE operation is stopped in the middle and the data of
accessing address is not guaranteed, so that write correct data again please.
It is not necessary waiting tWR (5msMax.) after stopping command by WP, because the device is standby state.
・The rising edge of the clock
which take in DO
SCL
D1 D0 ACK
SDA
AN ENLARGEMENT
SCL
・The rising edge
・of SDA
SDA D0 ACK
AN ENLARGEMENT
SDA
S
T SLAVE
A
R ADDRESS
T
A
C WORD
K
L
ADDRESS
A
C
K
L
D7 D6 D5 D4 D3 D2 D1 D0
A
C
K
L
DATA
AS
CT
KO
LP
tWR
WP cancellation
WP
invalid period
WP cancellation
effective period
No data will be written
Stop of the write
operation
Data is not
guaranteed
Fig.41 WP EFFECTIVE TIMING
●COMMAND CANCELLATION BY START AND STOP CONDITION
During a command input, it is canceled by the successive inputs of start condition and stop condition.(Fig.42)
But during ACK or data output, the device may output the SDA line LOW. In such cases, operation of start and stop
condition is impossible, so that the reset can't work. Execute the software reset in the cases. (Fig.39)
Operating the command cancel by start and stop condition during the command of Random Read or Sequential Read or
Current Read, internal address counter is not confirmed.
Therefore operation of Current Read after this is not valid. Operate a Random Read in this case.
SCL
SDA
1
0
1
0
START
CONDITION
STOP
CONDITION
Fig.42 COMMAND CANCELLATION BY START AND STOP CONDITION DURING
THE INPUT OF SLAVE ADDRESS
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